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IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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LIFE CYCLE COST ANALYSIS OF OVERLAY FOR AN URBAN ROAD IN
BANGALORE
Preethi.S1
, Radhakrishna2
, Raghavendra Prasad3
1
PG Student, 2
Associate Professor, 3
Research Scholar, Department of Civil Engineering, R. V. College of Engineering,
R. V. Vidyaniketan Post, Mysore Road, Bangalore 560059, India
Abstract
Pavements are subjected to severe condition of stresses and weathering effects from the day they are constructed and opened to traffic
mainly due to its fatigue behavior and environmental effects. Therefore, pavement rehabilitation is one of the most important
components of entire road systems. This paper highlights the design of concrete pavement with added mono fibers like polypropylene,
steel and hybrid fibres for a widened portion of existing concrete pavement and various overlay alternatives for an existing
bituminous pavement in an urban road in Bangalore. Along with this, Life cycle cost analyses at these sections are done by Net
Present Value (NPV) method to identify the most feasible option. The results show that though the initial cost of construction of
concrete overlay is high, over a period of time it prove to be better than the bituminous overlay considering the whole life cycle cost.
The economic analysis also indicates that, out of the three fibre options, hybrid reinforced concrete would be economical without
compromising the performance of the pavement.
Keywords: - Fatigue, Life cycle cost analysis, Net Present Value method, Overlay, Rehabilitation
--------------------------------------------------------------------***----------------------------------------------------------------------
1. INTRODUCTION
Road network in India has grown exponentially from 0.4
million km in 1951 to 3.32 million km presently with increase
in motor vehicles from 0.3 million in 1951 to 108 million in
2008 [1]. Due to this gigantic increase in traffic load, its
intensity, tire pressure, inadequate design of pavement
thickness and ill-drained effects, highway engineers are
finding themselves at a great disadvantage in keeping
pavements in a traffic- worthy state. The scarcity of resources
for the road sector in the past has lead to the adoption of stage
wise construction strategies with a short design period [2].
Therefore road construction in our country will be a never
ending process, with pavement strengthening to be a major
activity for many years to come. An overlay is a layer of
suitable thickness provided on top of an existing pavement to
improve its structural adequacy and riding quality. The two
principal options for overlay in terms of specification of
binder are [3]:
• Flexible overlay, consisting of granular layers and
bituminous layers
• Cement concrete overlay
Cement concrete overlay on top of an existing bituminous
surface is commonly known as white-topping. White-topping
based on thickness and bonding conditions are again classified
as: Conventional white-topping : thickness range : 200-300
mm, Thin white-topping : thickness range : 100-200 mm and
Ultra thin white-topping : thickness range : 50-100 mm.
Overlay practice in India: In India, the most common
strategy for pavement maintenance and rehabilitation was to
provide bituminous overlays on existing black topped surface.
This was mainly due to abundant supply of bitumen, in
addition to the comfort levels of construction methods among
engineers. In recent times all these advantages are reversed
and petroleum industry is using refined processing technology
leading to reduction in the production of bitumen thereby
increasing imports [4, 5]. The rapid developments in concrete
material technology and mechanization are favoring concrete
overlays as a sustainable option. A typical mix proportion of
concrete overlays by taking into consideration polypropylene
fiber, mineral admixtures like fly-ash, granulated blast furnace
slag, silica fume have shown increase in density of concrete
due to particle packing theory [6].
2. OBJECTIVES & SCOPE OF THE STUDY
The main objective of the research is to study the structural
adequacy of existing pavement and to design the overlay
alternatives along with cost evaluation of each alternative.
3. DATA ACQUISITION
3.1 Stretch Selected
The stretch selected is located in eastern part of Bangalore city
and acts as a link between NH-4 (Old Madras road) on north
western side and Old Airport road on south western side as
shown in Figure 1. This is one of the busiest stretches in the
city. The traffic in the area chosen was moderately dispersed

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IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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at all times of the day, since the either side of corridor is
populated with establishments like HAL, BEML limited,
Bagmane Tech park, HAL engine division etc. The road is 2
lane with a total length of about 3.8 km in which 2.7 km is
rigid pavement and the remaining 1.1 km is flexible pavement
as shown in Figure 2.
3.2 Benkelman Beam Deflection Study
Surface deflections of existing flexible pavements are usually
measured by Falling Weight Deflectometer (FWD) and
Benkelman Beam Deflection test (BBD). A good correlation
strength was obtained between FWD and BBD values in a
study done by Jundhare.D.R [9] on conventional white-
topping of 320 mm thickness. Benkelman beam deflection
study was done on the stretch, and the characteristic deflection
obtained was 1.67 mm.
3.3 Traffic Data
For the design purpose, analysis is being made on the number
of commercial vehicles of laden weight having 3 Tons or
more. From traffic analysis, the commercial vehicles per day
obtained for section 1 and section 2 was 1146 cvpd and 982
cpvd respectively.
Fig 1: Map showing the selected stretch
Fig2: Different pavement sections in the selected stretch
4. DESIGN OF SECTIONS
Design of flexible overlay has been done as per IRC:81-1997
using Benkelman Beam Deflection value and traffic in msa
[6]. Rigid overlay design has been done as the same
procedure for new pavement given in IRC: 58-2002 [7].
White-topping design is done as per IRC: SP: 76-2008 [8].
4.1. Section 1: Widening of Concrete Road
Existing single lane concrete road was to be widened on either
side. Concrete pavement combined with fibres where used for
this. Fiber reinforced concrete (FRC) is mixtures of cement
concrete containing short discrete, uniformly dispersed and
randomly oriented suitable fibrous material which increases its
structural integrity. The amount of fibers added to concrete
mix is measured as percentage of the total volume of
composites. Aspect ratio (l/d) is calculated by dividing fiber
length (l) by its diameter (d).The types of fibres used for the
design along with the flexural strength and obtained thickness
is given in Table 1.
Table 1: Thickness of concrete with different fibers
Concrete Flexural strength
,MPa
Thickness
obtained, mm
Plain 4.62 290
Polyproplyene 4.762 280
Steel 5.129 270
Hybrid 5.54 250

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4.2 Section 2: Flexible Pavement
The existing flexible pavement has developed distresses like
rutting. So overlay has to be provided as a rehabilitation
strategy. Flexible or concrete overlay can be provided over the
bituminous surface.
4.2.1 Design of Flexible Overlay
Based on Benkelman Beam deflection data and commercial
vehicles per day using IRC-81, the thickness of flexible
overlay has been found out to as 150 mm BM. The thickness
deduced is the overlay thickness in terms of BM construction.
The equivalent overlay thickness to be provided can b
determined using equivalency factors. So the total individual
thicknesses obtained are: BC thickness: 40 mm and DBM
thickness: 65 mm
4.2.2 Design of Thin White-Topping
Thin white-topping design is carried as per IRC; SP: 76-2008
and IRC: 58-2002. The thickness obtained was about 200 mm.
The cumulative fatigue life consumed is less than 1. Hence
design life is safe from fatigue consideration. Total of
temperature warping stress and highest axle load stress =
21.98 kg/cm2, which is less than 45kg/cm2, the flexural
strength.
5. ECONOMIC EVALUATION
The alternative methods of strengthening or repairing of roads
should be based on their durability rather purely by initial cost.
The cost comparison for such alternative strengthening/repair
methods should be based on the concept of life-cycle cost
analysis
5.1 Life Cycle Cost Analysis between Different Types
of Fibres in Concrete for Section 1
In Section 1 the existing concrete pavement has to be widened
with addition of fibres to enhance its performance. The
quantity of work item involved in section 1 per km length is
given in Table 2.
Table 2: Quantities of work item involved per km length
In the present analysis the rates considered are Rs. 5191/ Cum
for control concrete, Rs. 376/kg for polypropylene fibre, Rs.
140/kg for concrete with steel fibre. Inorder to obtain flexural
strength of 4.762 MPa for polypropylene fibre reinforced
concrete, the percentage of recron 3s fibre used was 0.036%
(900g/cum of concrete). Therefore its cost will be Rs. 5529/
Cum. Similarly cost of steel and hybrid fibre concrete was
found out to be Rs. 8691/ Cum and Rs. 9029.4/ Cum
respectively. Traffic volume survey was conducted at stretch 1
and the volume of commercial vehicles obtained is given in
Table 3.
Table 3: Traffic volume obtained from traffic survey
A study made by CRRI, New Delhi on Delhi-Agra (NH-2)
found that there will be saving of 14% in fuel on concrete road
as compared to bituminous road for commercial vehicles [9].
The parameters considered for life cycle cost analysis by Net
Present Value method is given in Table 4.
Control concrete
(cum)
Concrete with
polypropylene
fibre (cum)
Concrete
with steel
fibre (cum)
Concrete with hybrid fibre (cum)
Heavy traffic 1160 1120 1080 1000
Type Count
Bus 166
HCV 570
MAV 44
LCV 332

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Table 4: Parameters considered for analysis of section 1
Commercial Vehicles Per
Day 1146
Traffic growth rate 7.50%
Inflation 5.00%
Diesel Cost Rs.54.21/l
Fuel Savings 14.00%
Mileage 4kmpl
Annual Fuel Savings (Rs) CVPD*365*FuelSavings*Mileage*DieselCost
5.2 Economic Comparison between Flexible and
Concrete Overlay for Section 2:
It will be assumed that bituminous overlays need following
interventions during the analysis period: 10th, 20th years : 50
mm BC + 75 mm DBM for heavy traffic , 40 mm BC + 75
mm DBM for medium traffic [10]. Surface renewals are
provided as per MORTH as 25 mm BC once in 5 years. The
cost of ordinary repairs as per 2011 price is 2,10,000 Rs/ Km.
Quantity of work item involved per km length of road is given
in Table 5.
Road User Cost:
The user cost comprises of vehicle operating costs (VOC),
time cost of passengers and commodities in transit and
accident costs. In present analysis, only VOC is considered, it
being assumed that time costs and accident costs on both types
of surfaces are the same [11]. The parameters considered for
the analysis is given in Table 6.
Table 5: Quantities of work item involved per km length
Periodic renewal once in 5 years
Heavy traffic 7000 - 175 - -
Overlay once in 10 years
Heavy traffic 7000 455 280 - -
Table 6: Parameters considered for analysis
Parameter Value
CVPD 982
Traffic growth rate 7.5%
Inflation 5.00%
Diesel cost Rs.54.21/liter
Fuel savings 14.00%
Mileage 4 kmpl
Annual fuel savings (Rs) (cvpd x 365 x fuel savings x mileage x diesel cost)
Analysis period 30 years
Flexible overlay Tack Coat (sqm) DBM (cum) BC (cum) Concrete M-40 (cum)
Thin white topping
Heavy traffic 7000 455 280 1400

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The rates for calculation of initial cost of flexible and white
topping are taken from schedule of rates Bangalore 2011-
2012. In the present analysis the rates considered are Rs. 6975/
Cum for DBM, Rs. 8632/Cum for BC, Rs.12/Sqm for tack
coat and Rs. 5,191/Cum for M-40 cement concrete. From
traffic volume survey the count obtained was as given in Table
7.
Table 7: Traffic count at section 2
6. RESULTS AND DISCUSSION
From the analysis for section 1, the thickness of widened
portion of concrete was less when hybrid fibres are used. The
initial cost of hybrid fibres when used in concrete pavement
was less compared to steel fibres. In case of section 2, the
initial cost of concrete overlay is more compared to flexible
overlay. But in view of availability of cement in plenty within
the country and scarcity and rising prices of bitumen, as crude
oil prices in the International market are rising and bulk of
crude oil has to be imported from other countries it will be
prudent to consider rigid pavements. Initial cost of concrete
after addition of fibers at section 1 and cost of flexible and
rigid overlay at section 2 is given in Table 8 and 9
respectively. Life cycle cost analysis by net present value
method for two sections are given in Table 10 and 11.
Table 8: Initial cost of concrete at section 1per km length
Control concrete PFRC(recron-3s) SFRC HFRC
60.22 lakhs 61.92 lakhs 93.86 lakhs 90.29 lakhs
Table 9: Intial cost of overlay for section 2 per km length
Table 10: Net present analysis of concrete with different type of fibre for section 1
Roug
hness 2000 mm/km 2000 mm/km 2000 mm/km 2000 mm/km
Concrete Overlay Rs-
Lakhs
Concrete Overlay with
Polyproplyene fiber Rs-
Lakhs
Concrete Overlay with
steel fiber Rs-Lakhs
Concrete Overlay with
hybrid fiberRs-Lakhs
Years
CVP
D
Constru
ction/M
aintena
nce VOC
Total
Cost
Constru
ction/M
aintena
nce VOC
Total
Cost
Constru
ction/M
aintena
nce VOC
Total
Cost
Constru
ction/M
aintena
nce VOC
Total
Cost
0 1146 60.220 0.000 60.220 61.920 0.000 61.920 93.860 0.000 93.860 90.290 0.000 90.290
1 1232 0.776 0.065 0.840 0.776 0.065 0.840 0.776 0.065 0.840 0.776 0.065 0.840
2 1324 0.814 0.070 0.884 0.814 0.070 0.884 0.814 0.070 0.884 0.814 0.070 0.884
3 1424 0.855 0.075 0.930 0.855 0.075 0.930 0.855 0.075 0.930 0.855 0.075 0.930
4 1530 0.898 0.080 0.978 0.898 0.080 0.978 0.898 0.080 0.978 0.898 0.080 0.978
5 1645 0.943 0.086 1.029 0.943 0.086 1.029 0.943 0.086 1.029 0.943 0.086 1.029
6 1769 0.990 0.093 1.083 0.990 0.093 1.083 0.990 0.093 1.083 0.990 0.093 1.083
7 1901 1.039 0.100 1.139 1.039 0.100 1.139 1.039 0.100 1.139 1.039 0.100 1.139
8 2044 1.091 0.107 1.199 1.091 0.107 1.199 1.091 0.107 1.199 1.091 0.107 1.199
9 2197 1.146 0.115 1.261 1.146 0.115 1.261 1.146 0.115 1.261 1.146 0.115 1.261
10 2362 1.203 0.124 1.327 1.203 0.124 1.327 1.203 0.124 1.327 1.203 0.124 1.327
Type Count
Bus 154
HCV 416
MAV 38
LCV 374
Flexible overlay Concrete overlay
56.74 Lakhs 72.67 Lakhs

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11 2539 1.263 0.133 1.397 1.263 0.133 1.397 1.263 0.133 1.397 1.263 0.133 1.397
12 2730 1.327 0.143 1.470 1.327 0.143 1.470 1.327 0.143 1.470 1.327 0.143 1.470
13 2934 1.393 0.154 1.547 1.393 0.154 1.547 1.393 0.154 1.547 1.393 0.154 1.547
14 3154 1.463 0.166 1.628 1.463 0.166 1.628 1.463 0.166 1.628 1.463 0.166 1.628
15 3391 1.536 0.178 1.714 1.536 0.178 1.714 1.536 0.178 1.714 1.536 0.178 1.714
16 3645 1.613 0.192 1.804 1.613 0.192 1.804 1.613 0.192 1.804 1.613 0.192 1.804
17 3919 1.693 0.206 1.899 1.693 0.206 1.899 1.693 0.206 1.899 1.693 0.206 1.899
18 4212 1.778 0.221 1.999 1.778 0.221 1.999 1.778 0.221 1.999 1.778 0.221 1.999
19 4528 1.867 0.238 2.105 1.867 0.238 2.105 1.867 0.238 2.105 1.867 0.238 2.105
20 4868 1.960 0.256 2.216 1.960 0.256 2.216 1.960 0.256 2.216 1.960 0.256 2.216
21 5233 2.058 0.275 2.333 2.058 0.275 2.333 2.058 0.275 2.333 2.058 0.275 2.333
22 5626 2.161 0.296 2.457 2.161 0.296 2.457 2.161 0.296 2.457 2.161 0.296 2.457
23 6048 2.269 0.318 2.587 2.269 0.318 2.587 2.269 0.318 2.587 2.269 0.318 2.587
24 6501 2.382 0.342 2.724 2.382 0.342 2.724 2.382 0.342 2.724 2.382 0.342 2.724
25 6989 2.502 0.367 2.869 2.502 0.367 2.869 2.502 0.367 2.869 2.502 0.367 2.869
26 7513 2.627 0.395 3.022 2.627 0.395 3.022 2.627 0.395 3.022 2.627 0.395 3.022
27 8076 2.758 0.425 3.183 2.758 0.425 3.183 2.758 0.425 3.183 2.758 0.425 3.183
28 8682 2.896 0.456 3.352 2.896 0.456 3.352 2.896 0.456 3.352 2.896 0.456 3.352
29 9333 3.041 0.491 3.531 3.041 0.491 3.531 3.041 0.491 3.531 3.041 0.491 3.531
30
1003
3 3.193 0.527 3.720 3.193 0.527 3.720 3.193 0.527 3.720 3.193 0.527 3.720
NPV
@
12.00
% 62.234 0.909 63.144 63.752 0.909 64.662 92.270 0.909 93.179 89.083 0.909 89.992
Table 11: Life cycle cost analysis of section 2
Roughness 3000 mm/km 2000 mm/km
Flexible Overlay Rs-Lakhs Concrete Overlay Rs-Lakhs
Years CVPD
Construction
/Maintenanc
e VOC
Extra Fuel
Cost (Rs)
Lakhs Total Cost
Constructi
on/Mainte
nance VOC
Total
Cost
0 982 56.740 0.000 5.27 62.009 72.670 0.000 72.670
1 1056 3.103 0.059 5.66 8.825 0.776 0.057 0.833
2 1135 3.258 0.063 6.09 9.410 0.814 0.061 0.876
3 1220 3.421 0.068 6.55 10.034 0.855 0.066 0.921
4 1311 3.592 0.073 7.04 10.701 0.898 0.071 0.969
5 1410 21.247 0.078 7.56 28.890 0.943 0.076 1.019
6 1516 3.960 0.084 8.13 12.176 0.990 0.082 1.072
7 1629 4.158 0.091 8.74 12.990 1.039 0.088 1.127
8 1751 4.366 0.097 9.40 13.860 1.091 0.094 1.186
9 1883 4.584 0.105 10.10 14.790 1.146 0.102 1.248
10 2024 85.538 0.113 10.86 96.510 1.203 0.109 1.312
11 2176 5.054 0.121 11.67 16.849 1.263 0.117 1.381
12 2339 5.307 0.130 12.55 17.986 1.327 0.126 1.453

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IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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13 2514 5.572 0.140 13.49 19.202 1.393 0.136 1.529
14 2703 5.851 0.150 14.50 20.503 1.463 0.146 1.608
15 2906 34.609 0.162 15.59 50.361 1.536 0.157 1.692
16 3124 6.450 0.174 16.76 23.383 1.613 0.168 1.781
17 3358 6.773 0.187 18.02 24.976 1.693 0.181 1.874
18 3610 7.111 0.201 19.37 26.680 1.778 0.195 1.972
19 3880 7.467 0.216 20.82 28.503 1.867 0.209 2.076
20 4171 139.332 0.232 22.38 161.945 1.960 0.225 2.185
21 4484 8.232 0.249 24.06 32.542 2.058 0.242 2.300
22 4821 8.644 0.268 25.86 34.777 2.161 0.260 2.421
23 5182 9.076 0.288 27.80 37.169 2.269 0.279 2.548
24 5571 9.530 0.310 29.89 39.730 2.382 0.300 2.683
25 5989 56.375 0.333 32.13 88.840 2.502 0.323 2.825
26 6438 10.507 0.358 34.54 45.406 2.627 0.347 2.974
27 6921 11.032 0.385 37.13 48.549 2.758 0.373 3.131
28 7440 11.584 0.414 39.92 51.914 2.896 0.401 3.297
29 7998 12.163 0.445 42.91 55.518 3.041 0.431 3.472
30 8597 226.957 0.478 46.13 273.564 3.193 0.464 3.656
NPV @ 12.00% 142.219 0.824 84.246 227.290 73.350 0.799 74.150
CONCLUSIONS
The following broad conclusions can be drawn from the
present investigation on mono steel, mono polypropelene and
hybrid fibres in concrete pavements:
• The thickness of pavement slab with hybrid fibres is
less by 40 mm compared to mono steel and
polypropylene fibres separately.
• From NPV method, the life cycle cost of
polypropylene fibres was less than hybrid fiber and
steel fibers.
• When mono steel and hybrid fibres are considered
separately, hybrid fibers are cost effective and
perform better than other mono fibers.
• The life cycle cost analysis for 12 percent discount
rate and 5 percent inflation rate suggests that flexible
overlay becomes expensive than rigid overlay due to
its heavy maintenance inflow over the life period.
REFERENCES
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[3] Vandana tare, “ Overlay alternatives on flexible
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2006.
[4] Sinha. V.K, Satander Kumar and Jain. R.K,
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[8] Guidelines for the Design of Plain Jointed Rigid
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[9] “Tentative Guidelines for Conventional, Thin and
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[11] Manual on economic evaluation of highway projects in
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